Kids and Young Adult (YA) e-book sales in the U.S. grew by triple digits in February, reports the Association of American Publishers, as compared to relatively flat adult e-book sales figures. The total for e-book sales in the category is close to 25 million sold in January 2012.

The key contributing factor: adults are devouring YA e-books like The Hunger Games trilogy, and — still — Harry Potter. The Hunger Games franchise held the top three spots for the month of January on both the physical bestseller list and the Kindle paid bestseller list, appearing on USA Today’s bestseller list and taking first place for Amazon and Kindle sales. With the March release of the movie, stats on e-book sales to be released next month could be record-breaking.

On the Pottermore e-hub, which was announced last June, Harry Potter e-book sales reached close to 525,000 in the first month, totaling about $4.8 million. The Pottermore e-bookstore launched on March 27 as the exclusive place to buy Harry Potter e-books and digital audiobooks followed by the full Potter digi-verse on April 14.

Pottermore CEO Charlie Redmayne is thrilled that the Potter brand has legs on digital. "Over the past two weeks we've seen sales settle down, but they remain very significant, and way beyond what we originally budgeted for," he commented.

Redmayne said that due to Pottermore’s light-touch Digital Rights Management, piracy had diminished. "Obviously there were fears piracy would increase as a result of being DRM-free, and that sales of the e-books would cannibalise sales of the physical titles, but we were delighted to see sales of the physical books go up, and piracy come down."

There was a spike in piracy following the launch, but fans largely rejected illegal copies and preferred the honorable route. "We have demonstrated that if you make these books available in the way that people want them, and on a platform that is accessible to them, and at a price they are happy with, then generally people will chose to buy them." It also helps that Pottermore offers exclusive Potter content and games to keep the Harry Potter brand vibrant and engaging.

On the Pottermore website, the first two weeks saw 22 million visits from 7 million unique users, the average visit lasting 25 minutes and spanning 47 pages. Redmayne added that there have been 4.2 million attempts to concoct magic potions, but with a low success rate of 32%, 39.9 million "wizard duels" with the "full body bind" spell the most popular.

And in the all-important library category, the Potter e-books occupy 51 of 80 positions in OverDrive’s most downloaded titles in the U.S., U.K., Canada, and Australia.

Clearly, YA e-books are finding their own magic potion of successfully leveraging powerhouse franchises with online platforms that offer ease of access and smart marketing for an age-agnostic audience with a ravenous digital appetite.

Below, take a look back at how Rowling announced the Pottermore digital Potter universe last June: